GEA Grasso - Page 38

Grasso
Refri
g
eration Division
GRASSO SYSTEM CONTROL
Chap. 2 - 2 638660E_chapter2.doc 01.2004/1
Operation modes Signal for…
Name Explanation Start/Stop Capacity +/-
11 Remote + Net-Net.SP
Start/stop via network (MPI or Profibus-
DP) from a remote Master controller.
The capacity control is based on a
remote set point that is sent via the
network also.
Network
Network set
point
2.2 Explanation of symbols and characters used
Progression of a signal with time or information
Progression of a signal with time or information, the pre-event
history is irrelevant
Progression of a signal with time or information, the future is
irrelevant
Time at which a cause or condition begins (in text “• if..“)
Effect
(in text „→ then..“)
Figure 2.1, Explanation of symbols and characters
used
2.3 General starting conditions
The following conditions have to be fulfilled to begin start up of the compressor unit:
•
If
Start command, e.g. ’external on’ input equals 1 for operation mode 4 through 6
and
•
If
the ’start to start’ timer is not active
and
•
If
the ’stop to start’ timer is not active
and
•
If
no start limitation is active, e.g. Oil temperature too low, suction pressure too low or
discharge pressure too high
and
•
If
the digital input ’start release’ equals 1
and
•
If
no alarms are active
→
Then
the starting conditions are fulfilled